I've had an annoying dry cough for around 3 weeks now, and I don't even cough. I think it's the last lingering effect of a flu I had. A lot of people I have talked to have noticed a similar phenomenon; all the other symptoms of the flu go away, but the cough hangs around for like a month. Smoking certainly isn't helping the situation any, but you may have the same condition that so many others have right now.